The present invention generally relates to industrial robots used for painting a work in different colors by selectively using various spray guns, and particularly to a jig or a mounting/dismounting system used for mounting and dismounting a spray gun on such a painting robot.
In production of automobiles and the like, there is a demand to manufacture automobiles having different colors on a single production line. When performing painting in a plurality of colors using a single painting robot such a production line, a plurality of spray guns are used in correspondence to the color to be used. Thus, a desirable spray gun is selected and mounted on an arm of the painting robot. By repeating such a mounting procedure, the spray gun held by the robot is replaced and the color to be painted on the work is changed.
The spray gun is mounted on an adapter adapted to be mounted on the arm of the painting robot. When mounting such a spray gun on the arm of the robot, the arm is moved in accordance with a data fed to the robot previously by a teaching procedure, so that a tip end of the arm gradually approaches the adapter carrying the desired spray gun. Such an adapter is placed on a base. In other words, a plurality of adapters respectively carrying spray guns for different colors are placed in a row on respective predetermined positions on the base. However, such a procedure requires a precise control of the arm particularly when the arm engages with the adapter. In order to perform such a precise control of the arm of the robot, numerous data points specifying the movement of the arm having to be given. This means that the number of data points to be fed to the robot increases, and as a result, the speed of movement of the arm is slowed. Such a slow-down in the movement of the arm leads to a decrease in the efficiency of the painting operation.
Further, the conventional procedure to mount the spray gun on the arm of the robot sometimes causes a problem when the arm has accidentally moved the gun excessively, passing through a desired position. Such an accidental movement of the arm is particularly harmful when the arm is moved so as to engage with the adapter held on the predetermined position of the base. When the arm is moved excessively and the spray gun has moved passing through the predetermined position, the gun or the adapter carrying the gun may collide with various apparatus or devices provided on the base in a vicinity of the spray gun. In the moment, there is so far no solution proposed to prevent the movement of the arm which leads to the harmful collision of the spray gun with other apparatus and devices.